>>6422624 Repost from earlier - can confirm.

One of my favorite add-ons was disabled by the Firefox gods. For those who might still be having issues, I found an easy fix and now I'm comfy again….

Firefox Preferences Privacy and Security > Data Collection and Use > Allow Firefox to install and use Studies

(Once the fix is in place, you can un-check the 'Studies' option.)

https://www.forbes.com/sites/kateoflahertyuk/2019/05/05/firefox-extensions-are-broken-heres-what-to-do/#4e8fd07163ff